Abstracts of papers for

Previous issue vol. 42, no. 4 (2001)

vol. 43, no. 1 (2002)

Next issue vol. 43, no. 2 (2002)

Contents of issue 1, vol. 43

1. E. Włodarczyk : Parameters of the annular detonation wave front in an explosive gas mixture
2. E. Włodarczyk : Influence of casing and liner inertia of wedge cumulative war-head on displacement velocity of their explosively driven elements, and on active mass of explosive
3. K. Jach, J. Lis, M. Mroczkowski, R. Świerczyński and A. Wiśniewski : Numerical-experimental studies on penetration of multilayered targets containing ceramics
4. A. Kuczaj : Numerical modelling of blast waves generated by explosion of an elongated gaseous cloud
5. A. Gębura : Diagnosis of aircraft power transmission tracks based on the analysis of generator’s frequency
6. B. Żak : Optimization of ship's trajectory in collision situation
7. B. Żak : Collision situation of objects afloat as multiple complex motion

E. Włodarczyk : Parameters of the annular detonation wave front in an explosive gas mixture

The algebraic formulae are derived, which determine the hydrodynamic parameters of the detonation products (pressure, specific volume, particle velocity, temperature, and propagation velocity of the annular detonation wave) at the front of the spatially two-dimensional detonation wave (annular wave), cycle-initiated on the external surface of a cylindrical gas explosive mixture charge. The results can be applied, among other things, in computer simulation of the cumulation processes.

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E. Włodarczyk : Influence of casing and liner inertia of wedge cumulative war-head on displacement velocity of their explosively driven elements, and on active mass of explosive

The influence of casing and liner inertia of the wedge cumulative war-head on a displacement velocity of their explosively driven elements and on the explosive active mass, has been analysed in this paper. Simple algebraic formulae were derived to estimate the displacement velocity of the casing and liner elements, and of the explosive active mass. The results of theoretical calculations, obtained with the aid of these formulae, are in agreement with the experimental data. Key words: cumulation, condensed explosives, active mass of explosive.

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K. Jach, J. Lis, M. Mroczkowski, R. Świerczyński and A. Wiśniewski : Numerical-experimental studies on penetration of multilayered targets containing ceramics

In the paper we present the results of numerical and experimental studies of the impact of penetrators onto ceramic-composite and ceramic-metal targets. The main purpose of this paper is to show the possibilities of computer-aided interpretation of experimental results using "free particles" hydrocodes modelling of multilayered targets containing ceramics. Model for ceramics is based on the modified Steinberg's constitutive relations for non-damaged, ideal ceramic material. The model of the composite is based on the isotropic multilayered model of composite panels with different material characteristics in each layer. The numerical simulations and experiments were carried out for several combinations of ceramic/metal and ceramic/composite layers: Al₂O₃/aluminium, SiC/AlN/steel, AlN/SiC/steel, SiC/Al₂O₃/steel, AlN/Al₂O₃/steel and Al₂O₃/Dyneema. The exemplary results of our studies are shown. The results of theoretical and experimental investigations are in good agreement with one another.

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A. Kuczaj : Numerical modelling of blast waves generated by explosion of an elongated gaseous cloud

A numerical solution is given for the 2D problem of scattering of the detonation products of exploding cylindrical gaseous cloud. Numerical simulations have been performed for unconfined gaseous explosions for various proportions of the longitudinal-to-transverse dimensions of the cloud. The near field of air blast is highly asymmetrical and directional, thus simple engineering approximations of the blast parameters have been given for various directions of blast wave propagation.

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A. Gębura : Diagnosis of aircraft power transmission tracks based on the analysis of generator’s frequency

Power transmission tracks of various aircrafts usually exhibit different degrees of wear and tear. A diagnostic method based on the measurement of alternator's frequency modulation has been developed at the Air Force Institute of Technology. This method makes it possible to qualify the level of usual wear-and-tear of subassemblies and locate the defects during operation of the aircraft power transmission tracks. Algorithms of a quick and effective analysis of wear-and-tear for particular kinematic couples have been worked out. Basing on this method, a few prototypes of pocket the size testers were produced six years ago. They are combined with aircraft electric network and indicate the most worn subassemblies, as well as the level of wear-and-tear. At present, the diagnostic system based on measurements taken with these testers and furnished with a suitable computer database would increase the reliability of the whole aircraft systems. Until now, a diagnostic level has been qualified only on the basis of the so-called negative standard power transmission track, with at least one extremely worn-out element, and only for one aircraft type. Theoretical and experimental works go on simultaneously, with the aim to establish a more universal method.

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B. Żak : Optimization of ship's trajectory in collision situation

The paper present a method used to determine the minimum-time control of ships in a situation of collision with other objects afloat. It also includes the results of simulation study conducted by means of the method. Parallel approaching of a ship to an encountered object was studies, i.e. a situation generating a critical case -- collision of two ships.

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B. Żak : Collision situation of objects afloat as multiple complex motion

The paper present a mathematical model of a collision situation of object afloat. To describe it, the rules of a multiple complex motion were used. The paper contains also an analysis of the model presented and the conclusions drawn from it.

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